Sacroiliac Pain in Horses: Diagnosis, Physiotherapy, and What to Expect

Introduction

Sacroiliac (SI) pain is one of the most commonly discussed and frequently misunderstood diagnoses in equine practice. It is also one of the conditions where physiotherapy plays a particularly important role — not just in managing pain, but in addressing the underlying movement dysfunction that drives it. In this post, we explain what the sacroiliac joint is, how problems develop, and what a physio-led management programme looks like at RPM Equine.

What Is the Sacroiliac Joint?

The sacroiliac joint connects the pelvis (ilium) to the sacrum — the base of the spine. It is a large, relatively immobile joint stabilised by powerful ligaments, and it transmits the propulsive forces generated by the hindlimbs through to the spine and therefore the rider.

Because of its position and function, the SI joint is subjected to significant forces during work — particularly in disciplines involving collection, jumping, or lateral work. Over time, or following trauma (such as a slip or fall), the structures around the joint can become inflamed or painful, leading to a characteristic pattern of performance and movement changes.

Signs of Sacroiliac Pain in Horses

•       Reduced engagement from behind — the horse feels 'flat' or lacks power

•       Asymmetry in the hindquarters — one hip appearing higher than the other, or asymmetric muscling around the croup

•       Difficulty or reluctance in canter, particularly on one lead

•       Bunny hopping in canter — both hindfeet landing together rather than in sequence

•       Discomfort or resentment when pressure is applied over the SI region

•       Intermittent hindlimb lameness that does not respond clearly to distal flexion tests

•       Stiffness that warms out of work but returns with rest

Diagnosis

SI pain is notoriously difficult to diagnose definitively because the joint itself is not accessible to direct radiography or ultrasound in most horses. Diagnosis is typically based on a combination of:

•       Clinical examination — palpation, movement assessment, response to provocative tests

•       Diagnostic nerve blocks — if appropriate and directed by your vet

•       Nuclear scintigraphy (bone scan) — the most reliable imaging modality for SI pathology

•       Response to treatment — improvement following SI joint injection is often used to confirm the diagnosis

The Role of Physiotherapy

Physiotherapy is central to managing sacroiliac pain — both in the short term (addressing pain and secondary muscle changes) and in the long term (building the muscular support that protects the joint from further strain).

Addressing Secondary Muscle Changes

Horses with SI pain almost always develop secondary muscle tension and atrophy — particularly in the gluteals, hamstrings, and lumbar musculature. This is a response to pain and altered movement patterns, and it persists even after the primary pain source is treated unless it is specifically addressed.

•       Manual therapy to release gluteal and lumbar tension

•       Laser therapy and electrotherapy to manage pain and promote circulation

•       Targeted stretching to restore mobility through the hip and lumbar region

Rebuilding Muscular Support

The SI joint relies heavily on surrounding musculature for stability. Physiotherapy-prescribed exercise builds this support progressively:

•       Water treadmill: promotes symmetrical hindlimb movement and core engagement in a low-impact environment — one of our most effective tools for SI rehabilitation

•       In-hand hillwork: builds gluteal and hamstring strength progressively

•       Pole work: improves hindlimb engagement and proprioception

•       Lateral work under saddle: leg yield, shoulder-in, and travers build the oblique musculature that supports the SI joint

Prognosis

With appropriate veterinary management and a structured physiotherapy programme, most horses with SI pain can return to their previous level of work. Horses in jumping and dressage disciplines, where collection and lateral work place high demands on the SI region, may need ongoing maintenance physiotherapy to manage the condition long term.

At RPM Equine, we see many horses referred with SI pain and build bespoke programmes that combine treatment with progressive exercise prescription. The water treadmill is a core part of most of these programmes.

Concerned about sacroiliac pain in your horse? Book a physiotherapy assessment at RPM Equine — from £75. Based in Middlewich, Cheshire.